An observational study in Tobacco Use Behavior, Nicotine Dependence Tobacco Product and E-Cigarette Use, sponsored by University of Southern Denmark. Recruiting at 1 site in Denmark. Open to participants aged 15 Years to 25 Years. Per ClinicalTrials.gov, last updated 2026-11-09.
Sponsored by University of Southern Denmark · Observational
The §SMOKE Cohort Study aims to improve understanding of tobacco and nicotine use among adolescents and young adults in Denmark. The study focuses on a rapidly changing nicotine landscape that includes cigarettes, e-cigarettes, nicotine pouches, heated tobacco products, and other nicotine products.
The study is based on the hypothesis that tobacco and nicotine use during adolescence and young adulthood follows different developmental pathways and that individual characteristics, social influences, and environmental factors affect initiation, continued use, cessation, relapse, and switching between products. The study further hypothesizes that different patterns of tobacco and nicotine use are associated with differences in educational, health, and social outcomes.
By following young people over time, the study seeks to improve understanding of how tobacco and nicotine use develops, which factors influence these behaviors, and what consequences may be associated with different patterns of use. The findings will contribute to evidence supporting tobacco and nicotine prevention efforts and public health policy for adolescents and young adults in Denmark.
The §SMOKE Cohort Study is a national prospective longitudinal cohort study established to generate evidence on the development, determinants, and consequences of tobacco and nicotine use among adolescents and young adults in Denmark. The study was initiated in response to substantial changes in the tobacco and nicotine market, including the increasing availability and use of electronic cigarettes, nicotine pouches, heated tobacco products, disposable vaping products, and other emerging nicotine products. While surveillance systems provide important information on prevalence and trends in population-level tobacco and nicotine use, there is limited evidence on how the use of different products develops over time within individuals, the factors that influence transitions between products, and the longer-term consequences associated with different patterns of use.
The primary objective of the study is to establish a national cohort of Danish adolescents and young adults and follow participants over time in order to characterize trajectories and transitions in tobacco and nicotine use. The study aims to examine patterns of initiation, escalation, cessation, relapse, product switching, and multiple-product use, as well as to identify individual, psychological, interpersonal, and societal factors associated with these processes.
Participants will be recruited from the national §SMOKE survey conducted in Denmark in 2026. Approximately 10,000 individuals aged 15-25 years are expected to be enrolled and followed through annual data collections over a four-year period. Data collection consists of repeated questionnaire-based assessments designed to monitor tobacco and nicotine use behaviors, attitudes, perceptions, and related determinants. To ensure longitudinal comparability, a core set of measures will be retained across all follow-up waves. At the same time, selected questionnaire modules may be adapted during the study period to capture emerging tobacco and nicotine products, new patterns of use, changes in marketing practices, and developments in the regulatory environment.
The study is informed by a socioecological framework that recognizes tobacco and nicotine use as the result of interactions between factors operating at multiple levels. Survey measures therefore encompass tobacco and nicotine use behaviors as well as individual-level factors, including motivation for use, dependence, risk perceptions, mental health, well-being, and use of other substances; interpersonal factors, including family and peer influences; and societal factors, including exposure to tobacco and nicotine marketing, product availability, awareness of tobacco control measures, and perceptions of regulatory enforcement.
A key feature of the cohort is linkage of survey data to nationwide Danish administrative registers using the unique personal identification number assigned to all Danish residents. Register linkage enables prospective assessment of educational, health, labor market, demographic, and socioeconomic outcomes. Through these linkages, the study will examine the broader consequences of tobacco and nicotine use trajectories during adolescence and young adulthood.
Analyses will focus on understanding how tobacco and nicotine use evolves over time and identifying factors associated with transitions between use states and products. Longitudinal analytical approaches will be applied to examine developmental trajectories, transitions between patterns of use, and predictors of initiation, continuation, cessation, relapse, and product switching. Additional analyses will evaluate educational, health, social, and economic consequences associated with different patterns of tobacco and nicotine use. The study is intended to provide evidence that can support tobacco and nicotine prevention initiatives, inform regulatory decision-making, and strengthen the evidence base for public health policy targeting adolescents and young adults.
To support data quality and cohort retention, standardized data collection procedures will be used across study waves, and participant follow-up will include reminder procedures and retention activities. Analyses will incorporate appropriate methods to account for survey design, non-response, attrition, and missing data. Findings will be reported in accordance with relevant methodological and reporting standards for longitudinal observational research.
1,027 studies on the registry are indexed under Tobacco Use Disorder; 128 are open to participants now.
This study's planned enrollment of 10,000 is above the median of 129 across 82 observational studies indexed under Tobacco Use Disorder.
Browse Tobacco Use Disorder studies →University of Southern Denmark is the lead sponsor of 336 studies on the registry; 46 are open to participants now.
Counted across the registry records on this site, refreshed daily.
The study population consists of adolescents and young adults residing in Denmark who participate in the 2026 §SMOKE survey. Participants are recruited from a national population-based sample identified through the Danish Civil Registration System and invited through the Danish digital postal system (e-Boks). The cohort includes individuals aged 15-25 years at baseline and is intended to be broadly representative of young people living in Denmark. The study population encompasses individuals with varying tobacco and nicotine use patterns, including non-users, experimental users, current users, former users, and users of different tobacco and nicotine products such as cigarettes, e-cigarettes, nicotine pouches, and heated tobacco products.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Tobacco and nicotine use behavior among young people (aged 15-25 years)
Longitudinal tobacco and nicotine use trajectories
Patterns of tobacco and nicotine use over time, including initiation, cessation, relapse, product switching, exclusive product use, and multiple-product use.
Time frame: Baseline through 4 years
Transitions between tobacco and nicotine use states/behavior
Transitions between predefined or latent use states (e.g., non-use, experimentation, regular use, cessation, relapse, and multiple-product use) observed across follow-up waves.
Time frame: Baseline through 4 years
Educational, health, and social outcomes associated with tobacco and nicotine use trajectories
Educational attainment, healthcare utilization, mental health indicators, and labour market outcomes associated with different tobacco and nicotine use trajectories.
Time frame: Baseline through end of available register follow-up
Predictors of tobacco and nicotine use initiation and continuation
Associations between individual, psychological, interpersonal, and societal factors and subsequent initiation, continuation, cessation, relapse, and product switching of tobacco and nicotine products. Factors include dependence symptoms, risk perceptions, mental health, peer and parental use, marketing exposure, product availability, and exposure to tobacco control policies.
Time frame: Baseline through 4 years
Initiation of tobacco or nicotine product use
First reported use of any tobacco or nicotine product among baseline non-users.
Time frame: Baseline through 4 years
Cessation of tobacco or nicotine use
Transition from current use to sustained non-use of tobacco or nicotine products.
Time frame: Baseline through 4 years
Poly-product tobacco and nicotine use
Concurrent use of two or more tobacco or nicotine products.
Time frame: Baseline through 4 years
Nicotine dependence
Level of self-reported nicotine dependence measured using The Short Nicotine Dependence Index. The scale runs from 1 (lowest) to 9 (highest).
Time frame: Baseline through 4 years
Change in perceived relative health risk of tobacco and nicotine products compared with cigarettes
Change in perceived health risk of tobacco and nicotine products relative to cigarettes, assessed using a single survey item: "How would you rate the following products in relation to cigarettes in terms of health risks?"
Time frame: Baseline through 4 years
Health-related quality of life (QALYs)
Health-related quality of life associated with different tobacco and nicotine use trajectories and transition patterns, assessed using the EuroQol 5-Dimension Youth Version (EQ-5D-Y) and the Child Health Utility 9D (CHU9D). The EQ-5D-Y descriptive system consists of 5 dimensions (mobility, self-care, usual activities, pain/discomfort, and feeling worried, sad or unhappy), each with 3 response levels. Responses can be converted into a utility index score, with higher scores indicating better health-related quality of life. The CHU9D consists of 9 dimensions with 5 response levels each and can similarly be converted into a utility index score. Quality-adjusted life years (QALYs) may be estimated directly from participant-reported data or derived using published utility weights where appropriate.
Time frame: Baseline through 4 years
Plan to share: No — Individual participant data will not be shared because the study includes sensitive personal data and linked administrative register data that are subject to Danish data protection regulations and data access restrictions. Researchers may be able to apply for access to relevant data through the appropriate Danish authorities and data custodians, subject to required approvals.
Started Sep 2026 (actual). Primary completion is estimated for Dec 2030, 50 months after the start.
Of 27 observational studies under Tobacco Use Disorder, half reached primary completion within 42 months of starting (the median), counting those still running; a quarter within 17 and three quarters within 90. This study's planned 50 months is above that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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